This invention relates to an automatic closure device for use in combination with a pressurized container which has a liquid or pasty filling dischargeable as a foam, as well as a propellant, preferably a liquified gas and comprises a valve means spring-biassed into the closed position; and which closure device comprises an actuator head having a discharge orifice, a discharge duct in the actuator head which duct connects the discharge orifice with an entry port, remote from the orifice, in the actuator head and serving for connecting the latter to an outlet opening of the container controlled by the aforesaid valve means, the discharge duct and orifice being surrounded by an integral wall consisting, at the discharge orifice and the wall portion adjacent the latter, of two wall zones the contact edges of which at the discharge orifice are of equal length and abut each other in closed position, while, in open position, these contact edges merge with each other under an acute angle, one of these wall zones being elastically flexible and the other rigid; and a beak-shaped closing member having a lip portion and being associated with the actuator head in a manner such that the free end of the lip portion of the closing member rests against the elastically flexible wall zone from the outside of the latter at the discharge orifice, thus pressing the flexible wall zone in the closed position hermetically sealingly the rigid wall zone.
In my Monegasque U.S. Pat. No. 105874.983, issued May 7, 1974, which corresponds to U.S. Pat. Nos. 3,858,773 and 3,937,371, there is described a closure head of the type described above and serving for the automatic discharge of paste when compressing a collapsible tube equipped therewith. The embodiment illustrated in FIGS. 29 to 31 of the drawings of this patent is adapted for use with pressurized containers, however, manufacturing this known embodiment of a closure device from synthetic thermoplastic material by modern injection molding techniques is only possible in a complicated manner, requiring molds which are difficult to make and several production steps. Moreover it is necessary to fill the wide outlet channel 303 up to the discharge mouth 304 under the full internal propellant pressure prevailing in the pressure container, before the flexible wall zone 306 will be lifted off from the rigid wall zone 305, thereby deflecting the beak part 307 serving as a closing member and opening the discharge mouth 304 in the form of an arc (FIG. 30 of the Monegasque patent).
Those known closure devices for discharging foam which are presently on the market, for instance dispensers for shaving cream have a main drawback. After each dispensing, a residue of foam remains in and at the discharge mouth in contact with the surrounding air, and will dry, age and become decomposed by the influence of the oxygen in the air and by bacteria growing in the residue. When such a foam-dispensing pressurized container is used again after prolonged standing, it is unavoidable that a portion of the old decomposed foam residue infested with bacteria will first be brought onto the skin of the face or other parts of the user's body and will then be covered with fresh foam dispensed from the interior of the pressurized container, leading to infection of the skin.
Likewise, with most of the known containers, closing of the discharge valve of the latter will still permit an excess of foam to emerge from the discharge orifice and stick to the outside wall of the container (after-foaming). In order to overcome this drawback, British Pat. No. 1,365,472 describes an aerosol closure cap in which the residual foam emerging due to after-foaming is trapped in a reservoir provided in the interior of the closure cap. However, the drying and aging foam in the reservior remains in contact with the outside air and is likable to be contaminated by bacteria, and the amount of foam thus decomposing in the reservoir increases with each dispensing operation. Furthermore, the reservoir must be rather large to be big enough to accommodate the whole amount of foam due to after-foaming.
It is, therefore, an object of the invention to provide an automatic closure device of the type initially described having practically no after-foaming.
It is another object of the invention to provide an automatic closure device of the type initially described the operation of which is practically free from after-foaming and which permits a hygienically unobjectionable closing of the closure device on the pressure container.
These objects are attained and the drawbacks of the prior art are avoided by a closure device as initially described which is improved by having the discharge duct in the actuator head provided with a bend or knee zone and by having the flexible wall zone extend from the discharge orifice rearward at most to the beginning of the bended zone of the duct and by having the flexible wall zone, in the closure position effected by pressure of the free end of the lip portion of the closing member on the outside of the flexible wall zone, inclined relative to the central plane extending through the discharge duct between the flexible and rigid wall zones toward the discharge orifice, at a sufficiently small angle, so that when the spring biassed valve means of the pressurized container suddenly opens, the flexible wall zone will withstand the resulting sudden pressure buildup in the interior of the discharge duct.
In this improved closure device according to the invention, the actuator head is preferably surrounded by a cap, which is mounted on the pressurized container and has an opening at the top or on the side thereof accessible to manipulation and further has a lateral cut-out in which the portion of the actuator head containing the discharge orifice is lodged.
Furthermore, the portion of the actuator head which contains the discharge orifice is displaceable within the cap along the central axis of the pressurized container which axis extends through the valve thereof when the actuator head and the valve to which it is connected are depressed in the direction toward the interior of the pressurized container, whereby the said valve is opened. The return movement of the actuator head relative to the cap can be effected by the same spring which biasses the valve of the pressurized container into its closing position.
Preferably, the cross-sectional area of the discharge duct, at the discharge orifice and in the region of the duct extending to the bend thereof is, at maximum opening, at least equal to the cross-sectional area of the discharge duct at where the last-mentioned region merges with the knee zone.
More preferably, the region of the discharge duct extending from the bend to the discharge orifice is of constant cross-sectional area when the discharge orifice is maximally opened. The region of the discharge duct extending from the bend therein to the entry port is preferably also of a constant cross-sectional area.
It is particularly advantageous when in the closure device according to the invention, the part of the inner wall of the discharge duct constituted by the rigid wall zone is of concave cross-section at least at the rim of the discharge orifice and relative to the central duct axis through the orifice, and the free end of the lip portion of the closing member is of correspondingly convex shape whereby, in the closed position, the flexible wall portion is correspondingly convexly deformed and pressed with a hermetic seal onto the rigid wall zone.
According to a first preferred embodiment of the closure device according to the invention, the closing member is made integral with the top front wall of the cap and the spring-biased valve of the pressurized container acts in such a manner on the actuator head in the direction of the longitudinal axis of the region of the discharge duct extending from the bend in the latter to the entry port that the rigid wall zone and the flexible wall zone are pressed against one another and against the free end of the lip portion of the closing member, thereby hermetically sealing the discharge orifice. In this embodiment the actuator head is preferably slidingly guided in the interior of the cap and a movable member of the spring-biassed valve of the pressurized container can then be positively connected to the actuator head at the entry port of the latter, whereby, in the closed position, the actuator head is so displaced in the interior of the cap in the direction toward the top front wall of the latter, that the rigid wall zone of the discharge duct is pressed with hermetic seal against the flexible wall zone which in turn is at all times in contact with the free end of the lip portion of the closing member.
In this embodiment, the cap member is preferably provided with an outlet opening in which the discharge orifice of the actuator head is lodged, and the lip portion of the closing member extends adjacent the flexible wall zone to contact with its free end the rim of the flexible wall zone at the discharge orifice. The cap is then preferably provided with a rigid top frontal wall about an opening through which the actuator head is accessible, and the lateral outlet opening of the cap is located at at level below the lip portion, whereby the elastic wall zone in the actuator head always rests on the downwardly facing free end of the lip portion in the lateral outlet opening. The top frontal wall of the cap preferably has a recess in its periphery away from the lip portion through which recess the surface of the actuator head is accessible for displacement of the latter in a direction out of the cap. Preferably, this recess in the top frontal wall of the cap is located on the side of the actuator head approximately opposite the side thereof containing the entry port.
It is of particular advantage when the central axis of the region of the discharge duct extending from the bend therein to the entry port coincides with the central axis of the cap and the displacement of the actuator head relative to the cap when opening or closing the discharge orifice, takes place along this common axis.
Furthermore, arresting means can be provided whereby the cap and the actuator head can be locked together with the discharge orifice closed.
Moreover, a male connecting member can be provided to protrude inwardly from the inner face of the top frontal wall of the cap and a female connecting part can be provided on the outer face of the actuator head next adjacent the flexible wall zone, and facing away from the entry port, or the female connecting member is provided at the cap and the male member is provided on the outer face of the actuator head, whereby the male and female connecting members can be engaged as in a press button and whereby upon engagement of the two connecting members with one another the flexible wall zone and the lip portion are given a bias toward hermetically sealingly pressing on the rigid wall zone.
The top frontal wall of the cap can be provided with an opening extending through the male connecting member protruding from the inside of that wall, through the opening of which the outer face of the actuator head is accessible for actuation.
Advantageously the male connecting member consists of a sleeve bearing on its outside from its free end a radially outwardly protruding flange or bead, and the female connecting member can consist of a recess in the outer face of the actuator head turned away from the entry port which recess is provided with a radially inwardly extending flange or bead about the outer periphery of the recess, thus permitting snap engagement of the two members.
According to the closure device according to the invention, the actuator head is provided in its top end wall, which latter can be reached for actuation through an opening in the cap, with a recess the bottom of which is constituted by the outside surface of the flexible wall zone of the discharge duct, and, as an extension of the said recess, a cavity is provided in the end wall of the recess located toward the center of the top end wall, and the closing member comprises a deflectable arm the free end of which is biassed to press against the flexible wall zone at the discharge orifice, and a lever part connected to the opposite end of the said arm which lever part is inserted in the said cavity. The bias of the deflectable arm is such that the arm will yield at a determined increase of pressure in the discharge duct, whereby the flexible wall zone can be moved away from the rigid wall zone and the discharge orifice can be open as long as the increased pressure prevails in the duct.
Further objects of the invention will become apparent from the subsequent description thereof in connection with the drawings which illustrate non-limitative embodiments of the closure device according to the invention.